Panamera Diesel: Black Smoke & Power Loss Mystery

Hey there! I had a similar issue with my 2015 Porsche Cayenne Diesel last year (I have some experience working on cars, but not with complex issues like this). The symptoms you're describing sound exactly like what I experienced. Mine was diagnosed as a damaged wiring harness to the boost pressure actuator. Had it fixed at my local Porsche specialist, cost me around 155€ for the repair. The black smoke and power loss went away completely after that. Before we jump to conclusions though, could you share: How many miles/km on your Panamera? Have you scanned for error codes? When did these symptoms first appear? This will help me give you more specific advice based on my experience!

Thanks for your input! I've got 80224 KM on the clock, and these issues started showing up about a week after my latest service. I haven't scanned for codes yet, but I'm planning to do that tomorrow. Your experience with the wiring harness issue is really helpful, definitely sounds similar to what I'm dealing with. I'll check with my mechanic about that specific component.

Hey again! Thanks for the follow-up info. You know what's interesting, your situation is sounding even more similar to what I dealt with on my Cayenne now that you mention it started after a service. Mine actually began showing these symptoms about 10 days after routine maintenance too! With your mileage being around 80K km, you're pretty much where I was when I had my issue (I was at about 85K km). I really recommend getting that code scan done ASAP, for me, it showed P0299 and P0234, which pointed directly to the boost pressure control system. Quick tip from my experience, when you take it to the mechanic, ask them to specifically check if any wires got disturbed during the last service. In my case, they found that some wires had been accidentally pinched during the service work. It's a surprisingly common issue on these cars, especially around the engine bay where space is tight. Let me know what the scan shows, if it's the same codes I had, I can share some more specific details about what my repair process looked like. These Porsches are awesome cars but they can be a bit finicky with their boost systems!

Thanks so much for the detailed info! It's really reassuring to hear that your issue was relatively straightforward to fix. I just called my mechanic and scheduled an appointment for tomorrow morning, definitely going to mention the wiring harness and those specific codes you mentioned. It makes total sense about wires getting pinched during service, especially since mine started right after maintenance too. I'll get those codes scanned first thing and update the forum once I know what's going on. Really appreciate you taking the time to share your experience, it's helping me feel a lot less worried about what could've been a much bigger headache. Fingers crossed it's just a pinched wire like yours was!